Compounds having a heptaazaphenalene structure and their use have been variously studied. For example, it has been found that a compound having a heptaazaphenalene structure is useful as an ultraviolet ray absorbent and may be applied to cosmetics and medical drugs (see, for example, PTLs 1 to 3).
The application of a compound having a heptaazaphenalene structure to an organic light-emitting device has not been studied for a long time. In recent years, however, it has been found that a compound having a heptaazaphenalene structure is useful as a hole injection material (see PTL 4).